Presentation on theme: "Chapter 1 The Basics of Computing What is a Computer Types of Computers Computer Hardware Computer Software Communication Networks."— Presentation transcript:
Chapter 1 The Basics of Computing What is a Computer Types of Computers Computer Hardware Computer Software Communication Networks
What is a Computer? Input Processing Instructions Output A computer is a device that accepts input, manipulates it under a sequence of instructions (a program) and produces an output. This process is called the “Information Processing Cycle.” The output can be the result of a calculation or just an acknowledgement of the input.
For example… …an abacus is a kind of computer…
…so is a Slide Rule…
… and a Burrough’s Adding Machine… Advertisement from 1954
Handheld devices such as these are also computers…
However, we’re concerned with just 3 types of computers that are used for business information systems: Mainframes Minicomputers Microcomputers
Mainframe Computers industry term for a large computer “big iron” modularized to reduce overhead used in centralized computing environments large-scale computing server high volume high overhead processing used as large database servers Mainframes typically cost hundreds of thousands of dollars and are manufactured by companies such as Hitachi, IBM and Amdahl.
Diagram of a Simple Mainframe Configuration
Minicomputers smaller than a Mainframe larger than a PC (Microcomputer) have become the “mid-range” server IBM’s AS/400 is an example IBM AS/400
Microcomputers Personal Computers (PCs) desktop computing and client-server applications can serve both as a client and a serverclient server are generally categorized by the CPU type Intel – IBM compatibleIntel Motorola – Apple / MacIntosh / Power PCMotorola Sun - SPARCSun Microcomputers are what we think of as PCs. Although they cross the line at times, Sun Microsystems generally is thought to manufacture high-end PCs.
Basic Parts of a PC Mouse Keyboard Computer Case Monitor
Components of a Computer A computer needs the following devices to function: Input device(s) Processing Unit Output device(s) Storage device(s) This is the computer’s hardware…it is tangible.
Input Devices Keyboard Mouse Scanner Microphone Accept data for the computer to work with…
Processing Unit The Central Processing Unit, or CPU, is the brains of the computer. It controls all activity and performs operations on data based on its instruction set. The CPU is made up of several major units asinstruction set diagrammed below.
Processing Unit The CPU consists of these main elements: Control Unit - executes the instructions as interpreted Arithmetic / Logic Unit - performs mathematical and logical operations Registers - serve as the short term memory for the ALU’s computations and provides some reserved space for certain functions Clock Unit - generates pulses that determine the speed of instruction processing, the rate is measured in megahertz (Mhz)
Processing Unit The CPU has two main features: Its speed measured in millions of instructions per second, or MIPS Its word size is the number of bits the CPU can process at a time. An 32-bit processor manipulates 32 bits simultaneously.
System Memory A PC has three basic types of memory:memory Cache memory that is built into the CPU (not the CPU registers) called L1 or L2 cacheCache Read Only Memory (ROM) that is used to “boot” the system (among other applications)Read Only Memory boot Random Access Memory (RAM) which is the mainRandom Access Memory memory that acts like the workshop or desktop of the CPU
Output Devices The purpose of an output device is to presentoutput device electronic data (and the results of our work) in a form that can be understood and used. For example, think how hard it would be to use a computer without a monitor. Typical output devices on a PC are: Monitor Printer or Plotter Speakers
Output Devices Monitors: CRT – Cathode Ray Tube, like a Television LCD – Liquid Crystal Display TFT – Thin-Film Transistor Printers: Laser printers Inkjet Thermal Wax Dot-Matrix
Auxiliary Storage Devices These devices, also known as secondary storage, are where the PC stores data that must last from session to session. Basically speaking this is the permanent data storage. Though they differ in their technologies and methods of storage, the result is the same; the PC can easily retrieve the stored data for use at a later time. These components are many times referred to as Mass Storage Mass Storage devices.
Auxiliary Storage Devices Types of Auxiliary or Mass Storage devices are: Floppy disk drive Hard disk drive Optical disks (Compact discs, DVD) Zip drives Jazz or Bernoulli drives Tape drives Flash memory
Computer Software Two general types of software: System software Application software Software is computer instructions (Programs) and data. Anything that is electronically stored on a computer storage device is considered software. It is intangible and exists only electronically.
System Software Systems software are the programs that control the computer and manage its resources. Such as operating systems and system utilities. Operating systems perform the basic tasks of computing like managing the input and output of data and interpreting the instructions of the programs. System Utility software performs more basic functions such as file management or backup, but they must work under an operating system.
The Operating system connects components and directs the flow of data.
System Software Examples of Operating systems: Windows (XP, 2000, ME, 98, 95, 3.1, CE)Windows DOS (MS-DOS, DR-DOS, PC-DOS)MS-DOSDR-DOSPC-DOS Mac OS X Unix (Solaris, FreeBSD, SCO UNIX)SolarisFreeBSDSCO UNIX Linux Palm OS BeOS Operating systems are written to run on specific processors (platforms).
System Software Examples of Utility software: Anti-virus software Norton, McAfee, Sophos, Trend MicroNortonMcAfeeSophosTrend Micro File Management PKZip, WinZip, Norton SystemWorksPKZipWinZipNorton SystemWorks Disk Utilities PartitionMagic, System CommanderPartitionMagicSystem Commander Backup Retrospect, Backup MyPCRetrospectBackup MyPC Utility software is written to run under specific operating systems.
Application Software Application software consists of programs that help you work and play on the computer. This category includes word processors, games, spreadsheets, drawing and other “productivity” programs. This is the bulk of all software written. Application software is written to run under specific operating systems.
Communication Networks aka Computer Networks Two or more computers connected to share data and resources are “networked.” The simple idea behind computer networking is to allow users to access more information and give them access to devices not directly attached to their “local” system, such as printers or storage devices.
Computer Networks Two of the main types of computer networks are: LAN - Local Area Network WAN - Wide Area Network A LAN is comprised of computers located within close proximity, such as in an office or building. A WAN is a network of computers that are situated further apart, but still connected. Such a network might be of computers within a single state agency or of a multi-national corporation worldwide.
Computer Networks A PC must have a Network Interface Card installedNetwork Interface Card to connect it to a network. The cards, frequently called “nics”, come installed in many new computers as they are also used for cable modem and DSLcable modem DSL internet service. The computers can be configured in several ways, the most popular of these “architectures” are peer-to-peerpeer-to-peer and client/server. The first is a looseclient/server. connection of local computers with no central authority, the later relies on a “server” to manage the network and its resources.
A peer-to-peer network requires the computers to be connected to each other by a network cable, usually an “unshielded twisted pair” cable known as “CAT 5”.CAT 5 Connecting more then two computers require the use of a network hub as shown.
A client/server network uses a computer known as the server to manage the network and control accessserver to resources. The computers can be connected using various types of cable including CAT 5, coaxialcoaxial and fiber optical.fiber optical
Computer Networks Local Area Networks are configured in 3 basic topologiestopologies. These are either the logical or physical way the computers are connected. Each connection on the network is known as a node.node These topologies are: Star Bus Ring
A Star topology connects all the nodes directly to theStar server or to a connecting device such as a hub.hub
All nodes on a Bus topology are connected to aBus central line or backbone.
Nodes on a Ring topology are connected in a closedRing loop. This means that each node has two connections, one in and another out. Using this type of topology the data must travel through all the nodes.
Computer Network Software Computer networks use special operating systems and other system software to manage the network, its resources and its users. Network Operating Systems (NOS) should be very secure and robustNOS to provide reliable network services. Examples of such software are: Windows 2000 Server Novell NetWare Unix…too many flavors to link them allUnix Linux
The Internet The Internet is a worldwide computer network.Internet Actually it is a loose collection of networks. There is no central control or authority, all cooperation is voluntary to a degree… Users access the Internet by using a network that is connected to a “backbone” usually through an Internet Service Provider (ISP). The real accessISP path to the ‘net is through a Network Access Point (NAP).NAP
The World Wide Web The World Wide Web is a collection of computers connected via the Internet that support the use of documents written in HyperText Markup Language (HTML).HTML The “web” uses the HyperText Transfer Protocol (HTTP) as the standard for the formatting andHTTP transmission of these documents. Not every server on the ‘net uses HTTP, and therefore is not part of the Web.
The Internet is very large and diverse, there is no one method of access and there are many protocols used such as: NNTP - Network News Transfer Protocol forNNTP newsgroups SMTP - Simple Mail Transfer Protocol for sendingSMTP FTP - File Transfer Protocol used for sending filesFTP It’s a wonder it works so well, much less at all. Hobbes' Internet Timeline: